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Topic: Mantle (geology)


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In the News (Sun 26 May 19)

  
  Mantle (geology) - Wikipedia, the free encyclopedia
Typical mantle rocks have a higher portion of iron and magnesium, a higher magnesium to iron ratio, and a smaller portion of silicon and aluminium than the crust.
The convection of the Earth's mantle is a chaotic process (in the sense of fluid dynamics), which is thought to be an integral part of the motion of plates.
Mantle Viscosity and the Thickness of the Convective Downwellings retrieved on December 17, 2005
en.wikipedia.org /wiki/Mantle_(geology)   (1369 words)

  
 Encyclopedia :: encyclopedia : Mantle (geology)   (Site not responding. Last check: 2007-11-01)
The Earth's mantle is the layer in the structure of the Earth that lies directly under the Earth's crust and above the Earth's outer core.
The convection of the Earth's mantle is a chaotic process (in the sense of fluid dynamics), which is thought to drive the motion of plates.
The pressure at the bottom of the mantle is ~140 GPa (1.4 Matm).
www.hallencyclopedia.com /Mantle_(geology)   (852 words)

  
 [ whollyshift.info | Mantle (geology) Resources ]   (Site not responding. Last check: 2007-11-01)
This tubby layer of mantle und the crust bureaucratic paperwork the lithosphere, und cools principally by convection.
The convection of the Earth's mantle is a chaotic customary (in the perception of fluid dynamics), which is scrutiny to be an requisite affiliate of the of plates.
In the upper mantle, the silicates are inclusive riskless (localised districts with microscopic gangs of melt exist); however, as the upper mantle is both hot und concealed by somewhat embryonic pressure, the rock in the upper mantle has a somewhat close viscosity.
www.whollyshift.info /Mantle_%28geology%29   (1443 words)

  
 Mantle (geology) - Biocrawler   (Site not responding. Last check: 2007-11-01)
Typified by peridotite, dunite, and eclogite, mantle rocksalso possesses a higher portion of iron and magnesium and a smaller portion of silicon and aluminium than the crust.
Although these temperatures far exceed the melting points of the mantle rocks, particularly in deeper ranges, they are almost exclusively solid.
Although there is a tendency to larger viscosity at greater depth, this relation is far from linear, and shows layers with dramatically decreased viscosity, in particular in the upper mantle and at the boundary with the core [1] (http://www2.uni-jena.de/chemie/geowiss/geodyn/poster2.html).
www.biocrawler.com /encyclopedia/Mantle_(geology)   (929 words)

  
 Rheid - Wikipedia, the free encyclopedia
In geology, a rheid is a solid material that deforms by viscous flow.
For example, the Earth's mantle is believed to undergo convection over long time scales.
Since the mantle is known to be solid (it supports the propagation of shear waves), it must be behaving as a rheid.
en.wikipedia.org /wiki/Rheid   (187 words)

  
 AllRefer.com - mantle (Geology And Oceanography) - Encyclopedia
mantle, portion of the earth's interior lying beneath the crust and above the core.
No direct observation of the mantle, or its upper boundary, has been made; its boundaries have been determined solely by abrupt changes in the velocities and character of seismic waves passing through the earth's interior (see seismology).
Samples of the upper mantle may be provided by some volcanic eruptions in ocean areas, e.g., the Hawaiian Islands.
reference.allrefer.com /encyclopedia/M/mantle.html   (356 words)

  
 The trans-Mexican Volcanic Belt
Slab detachment of the deeper and denser part of the plate was initiated in the southern Gulf of California area by the influx of progressively younger oceanic lithosphere at the paleotrench that produced an increasing coupling between the Magdalena microplate and the overriding North American plate.
The absence of seismicity and the presence of low-density mantle beneath the arc are consistent with the detachment model that predicts the upwelling of hot, sub-slab material into the slab gap.
The upwelling of an enriched mantle was proposed by Marquez et al.
www.mantleplumes.org /Mexico2.html   (2495 words)

  
 Inside the Earth [This Dynamic Earth, USGS]   (Site not responding. Last check: 2007-11-01)
The mantle, which contains more iron, magnesium, and calcium than the crust, is hotter and denser because temperature and pressure inside the Earth increase with depth.
As a comparison, the mantle might be thought of as the white of a boiled egg.
The upper part of the mantle is cooler and more rigid than the deep mantle; in many ways, it behaves like the overlying crust.
pubs.usgs.gov /gip/dynamic/inside.html   (485 words)

  
 Siberia
Because surficial uplift in response to thermal expansion is a necessary consequence of the arrival of anomalously hot, plume-related material in the upper mantle, the geologic record shows conclusively that Siberian flood-volcanic volcanism was not plume related.
These and other authors suggest the existence of convecting, hot cells and have noted that normal mantle geothermal and melting curves are such that partial melting is the normal state for much of the upper mantle.
If the upper mantle is partially molten and enriched (Anderson, 1989, 1996), then only slight extension in the lithosphere is needed to allow intrusion and extrusion, and magma ascent will be focused at lithospheric discontinuities (King and Anderson, 1995).
www.mantleplumes.org /Siberia.html   (5884 words)

  
 Yale University - Department of Geology and Geophysics
Transfer of heat and matter in the Earths mantle and crust is a fundamental manifestation of differentiation that drives nearly all dynamic Earth systems.
mantle melting beneath subduction zones and hotspots, and the role of recycled crust in basaltic magmatism.
dynamics of the deep mantle, its volatile budgets, and influence of volatiles on mantle convection.
www.geology.yale.edu /research/geochempet   (224 words)

  
 Geology 100 Telecourse Introductory lecture Part 2
All crustal rock is less dense than mantle rock so it floats on the denser mantle like a block of wood floats on water.
Lithosphere -- Is rigid and is composed of the Crust + Uppermost Mantle
The lithosphere is solid and consists of the crust and uppermost mantle.
dl.ccc.cccd.edu /classes/telecourses/geology100/IntroLecture2.htm   (2026 words)

  
 UC Davis Geology: AGU Meeting Abstracts
A long-standing question in mantle dynamics concerns the scale of heterogeneity in the mantle.
Mantle convection tends to both destroy (through stirring) and create (through melt extraction and subduction) heterogeneity in bulk and trace element composition.
At the Summer 2004 CIDER workshop on Relating Geochemical and Seismological Heterogeneity in the Earth's Mantle, an interdisciplinary group evaluated scales of heterogeneity in the Earth's mantle using a combined analysis of geochemical data, seismological data and results of numerical models of mixing.
www-geology.ucdavis.edu /www/pubs/agu04/kellogg2_04.html   (482 words)

  
 Plate tectonics: a paradigm under threat
Bonatti, E. Subcontinental mantle exposed in the Atlantic Ocean on St Peter-Paul islets.
Pavlenkova, N. Crustal and upper mantle structure and plate tectonics.
Saxena, M. N., & Gupta, V. Role of foredeep tectonics, geological and palaeontological data, gravity tectonics in the orogeny and uplift of the Himalayas, vis-a-vis continental drift and plate tectonics concepts.
ourworld.compuserve.com /homepages/dp5/tectoref.htm   (3509 words)

  
 Deep Squeeze: Experiments point to methane in Earth's mantle: Science News Online, Sept. 25, 2004   (Site not responding. Last check: 2007-11-01)
During a simulation of the conditions in Earth's mantle, this bubble of methane formed when researchers mixed iron oxide, calcite, and water at high temperature and pressure.
Still, he says, the idea that hydrocarbon fuels could form in the mantle and rise to Earth's surface is compelling.
However, when one considers the size of the mantle in terms of storing fossil fuels, "that's a significant fraction of the planet's volume," he says.
www.sciencenews.org /articles/20040925/fob7.asp   (690 words)

  
 GEOLOGY   (Site not responding. Last check: 2007-11-01)
Mantle (B) is approximately 2885 kilometers thick and is the middle layer of the Earth.
The Mantle is made up of minerals rich in the elements iron, magnesium, silica, and oxygen.
It is seperated from the crust by a sharp change to higher density and seismic velocity, and more mafic composition.
visearth.ucsd.edu /VisE_Int/platetectonics/earthlayers.html   (195 words)

  
 Biblio: Plate Tectonics
Bartolini, A., and R.L. Larson, Pacific microplate and the Pangea supercontinent in the Early to Middle Jurassic, Geology, 29, 735, 2001.
McQuarrie, Raising the Colorado Plateau, Geology, 28, 91, 2000.
Peacock, Are the lower planes of double seismic zones caused by serpentine dehydration i subducting oceanic mantle [re: causes of deep focus earthquakes], Geology, 29, 299, 2001.
www.columbia.edu /~vjd1/biblio_tectonics.htm   (3110 words)

  
 Mantle Structural Geology From Seismic Anisotropy (ResearchIndex)   (Site not responding. Last check: 2007-11-01)
This can be inferred both from direct seismic observations of shear wave splitting from teleseismic shear waves, as well as the petrofabric analyses of mantle nodules from kimberlite pipes.
The anisotropy is principally due to the strain-induced lattice preferred orientation (LPO) of olivine.
The combined use of these mantle samples, deformation experiments on olivine, and numerical modeling of LPO, provides a...
citeseer.ist.psu.edu /406309.html   (202 words)

  
 mantle   (Site not responding. Last check: 2007-11-01)
The "middle layer" of the Earth, lying between the crust and the core.
The upper part, the asthenospheric mantle, is the source for the vast majority of magmas in the Earth, produced by melting during upwelling (it is incorrect to think of the mantle as having long-lived "pods" of melt [magma] that are "just waiting" to be released).
Compositionally, the mantle is more primitive than basaltic magma, which is reflected in a greater abundance of the mineral olivine in the mantle.
www.geology.wisc.edu /~g111/Terms/mantle/mantle.htm   (89 words)

  
 Vic Camp - Volcano-tectonic Environments
With a thickness of about 100 km, the lithosphere is composed of an upper layer of crust (~7 km thick under the oceans, and ~35 km thick under the continents) and a lower, denser layer of the earth's upper mantle.
(basaltic) magmas are generated directly from the mantle, either within the asthenosphere or within the overlying mantle lithosphere.
(basaltic-to-andesitic) magmas appear to be derived from the melting of hydrated lithospheric mantle.
www.geology.sdsu.edu /how_volcanoes_work/Volcano_tectonic.html   (509 words)

  
 Russ Pysklywec | Department of Geology at the University of Toronto
Coupled mantle-crust-climate dynamics; global and regional mechanisms of tectonic processes--orogenesis, basin formation; GPS and active tectonics, structural geology; mantle convection.
Pysklywec, R. Mitrovica, and M. Ishii, Mantle avalanche as a driving force for tectonic reorganization in the southwest Pacific, Earth Planet.
Pysklywec, R. Beaumont, and P. Fullsack, Modeling the behaviour of the continental mantle lithosphere during plate convergence, Geology, 28(7), 655-658, 2000.
www.geology.utoronto.ca /facultypysklywec.htm   (290 words)

  
 Vasilevsky's Curriculum Vitae   (Site not responding. Last check: 2007-11-01)
Tychkov S.A., Rychkova E.V., Vasilevskii A.N. Interaction between a plume and thermal convection in the continental upper mantle //Russian Geology and Geophysics, 1998, V.39, N 4.
Tychkov S.A., Rychkova E.V., Vasilevskii A.N., Chervov V.V. Thermal convection in the continental upper mantle and its effect in geophysical fields //Russian Geology and Geophysics, 1999, V.40, N 9.
Tychkov S.A., Rychkova E.V., Vasilevskii A.N. Thermal convection in the upper mantle under a lithospheric plate of variable thickness //Physics of the Solid Earth, 1999, V.35, N 9.
geology.uiggm.nsc.ru /uiggm/geodynam/lab818/geod/vasil_cve.html   (244 words)

  
 Geologic Glossary J through N   (Site not responding. Last check: 2007-11-01)
The outer layer of solid rock that includes the crust and uppermost mantle.
The uppermost part of the mantle is rigid and, along with the crust, forms the 'plates' of plate tectonics.
The mantle is made up of dense, iron and magnesium rich (ultramafic) rock such as dunite and peridotite.
www2.nature.nps.gov /geology/usgsnps/misc/glossaryJtoN.html   (1054 words)

  
 Geology Department and Courses   (Site not responding. Last check: 2007-11-01)
The Department of Geology seeks to teach and model for a student how data on earth processes and structures are understood and evaluated within interpretive frameworks, especially in relation to understanding earth history.
Students earn the master of science degree in geology by specializing in one of three areas: (1) soft-rock geology, (2) hard-rock geology, or (3) solid-earth geophysics.
The master’s degree program in the Department of Geology requires a bachelor’s degree in Geology or the equivalent undergraduate geology courses in some related degree program.
www.icr.edu /geology/index.html   (1210 words)

  
 My Publications - Department of Geology - University of Maryland
McDonough, W. (1990) Constraints on the composition of the continental lithospheric mantle.
Jochum, K.P., McDonough, W., Palme, H. and Spettel, B. (1989) Compositional constraints on the continental lithospheric mantle from trace elements in spinel peridotite xenoliths.
1987 McDonough, W. and McCulloch, M.T. (1987) The southeast Australian Lithospheric Mantle: Implications for its Growth and Evolution.
www.geol.umd.edu /~mcdonoug/pubs.htm   (1481 words)

  
 Category:Geology - Wikipedia, the free encyclopedia
Articles and media on this topic in other Wikimedia projects can be found at: Commons Category Geology
The main article for this category is Geology.
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en.wikipedia.org /wiki/Category:Geology   (80 words)

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